66 year old Caucasian male construction worker presents with the lesion shown. Biopsy reveals the following histopathology. What is the likely diagnosis?

Conjunctival intraepithelial neoplasia grade 3

Primary acquired melanosis

Pterygium

Squamous cell carcinoma

Board review answer #1

A. Conjunctival intraepithelial neoplasia grade 3

The patient is an older, light skinned male likely with significant UV exposure, putting him at higher risk for the conditions listed in the choices. The clinical image shows a gelatinous conjunctival lesion with feeder vessels at the limbus in the interpalpebral zone. The biopsy shows thickened conjunctival epithelium with loss of the normal maturation sequence. There is a proliferation of dysplastic squamous cells with high nuclear:cytoplasmic ratios, mitotic activity, hyperchromatic ad pleomorphic nuclei involving > 2/3 of the epithelial thickness (conjunctival intraepithelial neoplasia 3 / severe dysplasia). The basement membrane is intact.

Primary acquired melanosis (choice B) is a proliferation of intraepithelial melanocytes that typically grow in a nested pattern.

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